Implantable electrical stimulation systems have proven therapeutic in a variety of diseases and disorders. For example, spinal cord stimulation systems may be implanted in the spinal cord to treat chronic pain syndromes and in the brain to treat refractory chronic pain syndromes, movement disorders, and epilepsy. Peripheral nerve stimulation systems may be used to treat chronic pain syndrome and incontinence. In some cases, paralyzed extremities in spinal cord injury patients may be treated using functional electrical stimulation. Moreover, electrical stimulation systems can be implanted subcutaneously to stimulate subcutaneous tissue including subcutaneous nerves such as the occipital nerve.
In general, a stimulator includes a control module (with a pulse generator), one or more leads, and an array of stimulator electrodes mounted on the one or more leads. The stimulator electrodes are placed in contact with (or near) the nerves, muscles, or other tissue to be stimulated. The pulse generator in the control module generates electrical pulses that are delivered through the electrodes to body tissue.